This project proposes to investigate the role of quantitative computed tomography (QCT) in evaluating tumor and normal lung tissue responses to unconventional radiation delivery schema (URDS). A comprehensive CT data-base and analytic program will be developed to: (1) define trends in CT density changes in tumor and normal lung tissues as a function of time, dose and volume; (2) investigate correlations between CT trends, parallel chest roentgenograms and physical examination findings; (3) validate the use of trends in CT-density changes as early indicators of both tumor responses and alterations in healthy lung tissues; (4) quantify tumor response/control, normal tissue reaction and compensatory lung changes. The unconventional treatment schemes include combinations of upper half-body irradiation (UHBI), loco-regional and local portals; hyperfractionation, conventional and hypofractionation; combination hypofractionation radiotherapy and chemotherapy. Radiation-induced changes in the CT number (density) of normal and tumoral tissue will be the basis of our analyses of responses. The analyses will be supplemented by corroborative findings from chest radiographs and physical examinations. A dedicated CT scanner/simulator will be used to obtain patient scan series before, during and after radiotherapy. Statistical techniques will be developed to analyze variations in quantitative CT measures and thereby demonstrate tissue/target changes. The techniques will include Kalman Filter analyses of statistical parameters of identical regions-of-interest (ROI) of the image data. The distributions of CT-density within ROI's and their changes as treatment progresses, will also be correlated with tissue alterations. The proposal plans to quantitatively evaluate CT-density changes: (1) to derive quantitative measures of tumor regression/control and tissue toxicity; (2) for enabling early recognition of subtle pneumonopathic changes; and (3) to define indices of efficacy for the comparative evaluation of various treatment schemes.